Help Opening a Port on a Cisco Router

You can only have 1 ACL bound towards in interface-in / interface-out.

If you apply your ACL to your interface-in it will only check your inbound traffic on that interface.
If you apply your ACL to your interface-out it will only check your outbound traffic on that interface.
If you apply on both, ACL to in and out traffic.

The two way communication is only necesarry if you have an ACL applied to the interface in/out.

In this case the ACL 150 is probably applied towards your interface in or out.

If traffic from host A -> host B is blocked, no connection can be created between these two... so B can also not 'connect' to A.

(you can try ICMP for instance)